Inkjet printers include printhead assemblies having one or more printheads that operate by ejecting drops of ink onto a print medium through a plurality of printhead nozzles. Modern inkjet printers are capable of producing printed images onto a plurality of media types, including full-bleed (i.e., borderless) photos. When printing borderless photos, inkjet printers actually print an image that is larger than the target media (e.g., paper), which causes an overspray of waste ink around the perimeter of the paper. Inkjet printers also generate waste ink by purging the printhead nozzles prior to printing an image to ensure that the nozzles are clear. If not properly managed and disposed of, waste ink can cause a number of printing problems including clogged printhead nozzles and reduced print quality.
In known printer configurations, waste ink is often captured using absorbent pads made from fiber or open cell foam, which draws the ink away from the top surface of the pads. Although effective for absorbing waste ink, the pads have a limited volume of ink that can be absorbed. In addition, depending on environmental conditions and the type of ink being used, the ink does not always wick fully into the absorbent pad and can lead to a build up of stalagmites (generally conical deposits of build-up from ink drops) that further reduce the level of absorbency of the pads and contribute to print problems.
Further, the absorbent pads must generally be positioned just beneath the paper to prevent the velocity of the ink from slowing to a point where the ink droplets turn into an aerosol, which interferes with the functionality of the printhead components as well as the overall quality of the printed image. To prevent this, the absorbent pads must generally be captured within a few millimeters (approximately 5 mm) of the printhead surface. The close proximity of the pad with respect to the printhead assembly limits the size of the pad and increases the risk of stalagmite build up that clogs the printhead nozzles.
In other known printer configurations, overspray trays are used to capture waste ink. In some cases, overspray trays are more advantageous than absorbent pads in that the capacity of the trays is not limited by the absorbent volume of the pads. However, like the absorbent pads, overspray trays must be mounted in close proximity to the printhead surface to prevent the ink from turning into an aerosol. As a result, overspray trays generally have a raised collection surface for receiving waste ink droplets. However, to be effective in removing waste ink, the ink droplets must drip down into the bottom of the tray. This approach works well with some inks, but not with others. For example, pigmented inks, especially in hot or dry environments, do not generally flow well and can quickly build up stalagmites on the raised collection surface. Moreover, replacing overspray trays is often undesirable because they are generally open at the top and filled with waste ink that is likely to spill when moved or tipped.
Finally, another method used in some inkjet printers is to avoid collection and removal of waste ink all together by providing a larger paper size and trimming off the edges to obtain a borderless photo. In this way, waste ink is simply absorbed by the extra paper and discarded. Unfortunately, this method greatly increases the cost of the printer by requiring a paper cutting mechanism and produces a significant amount of paper waste.
Accordingly, the embodiments described hereinafter were developed in light of these and other drawbacks associated with known waste ink collection systems.